On Thu, 6 Jul 2006 14:44:22 +0200
"Diego 'Flameeyes' Pettenò" <flameeyes@gentoo.org> wrote:

> On Thursday 06 July 2006 14:35, Kevin F. Quinn wrote:
> > This could easily be done by configure
> > scripts; perhaps it would be a good idea to look into writing some
> > autoconf macros.
> Actually there's little need, you can simply use the #ifdef in the
> code, unless you have separated source files for MMX, SSE and so on
> (that might as well be), but even then, it's really trivial to
> autoconf.

Yep; I've seen that several packages do it the #ifdef way, which is
ideal as we don't need to do set any configure stuff at all then (I
guess those packages don't have configure options/use flags to select
between mmx, sse etc anyway).

> The problem is that many autoconf scripts do it the other way around,
> by forcing -march or -mcpu (that is deprecated by -mtune too) deduced 
> from /proc/cpuinfo.

Ooh; that's nasty.  Let me guess - mplayer ... yeah; what a surprise.
Presumably we disable such trickery if we see it, as it makes the
target code depend on the build system which is obviously wrong - at
least for Gentoo.

-- 
Kevin F. Quinn